Upcoming ARISS Contact Schedule as of 2020-11-27 17:30 UTC
Upcoming ARISS Contact Schedule as of 2020-11-27 17:30 UTC
Quick list of scheduled contacts and events:
Amur State University, Blagoveshchensk, Russia, direct via TBD
The ISS callsign is presently scheduled to be RSØISS
The downlink frequency is presently scheduled to be 145.800 MHz
The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html
The scheduled astronaut is Sergey Ryzhikov
Contact is go for Thu 2020-12-03 08:45 UTC
Scuola Secondaria di I grado “Anna Frank”, Pistoia, Italy, telebridge via IK1SLD
The ISS callsign is presently scheduled to be OR4ISS
The downlink frequency is presently scheduled to be 145.800 MHz
The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html
The scheduled astronaut is Victor Glover KI5BKC
Contact is go for: Fri 2020-12-04 12:25:22 UTC 50 deg
Tecumseh High School Electronics and Amateur Radio, Tecumseh, OK, direct via K5THS
The ISS callsign is presently scheduled to be NA1SS
The downlink frequency is presently scheduled to be 145.800 MHz
The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html
The scheduled astronaut is Shannon Walker KD5DXB
Contact is go for: Fri 2020-12-04 18:33:30 UTC 78 deg
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The latest information on the operation mode can be found at https://www.ariss.org/current-status-of-iss-stations.html
The latest list of frequencies in use can be found at https://www.ariss.org/contact-the-iss.html
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A multi-point telebridge contact means that each student will be on the telebridge from their own home.
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ARISS is very aware of the impact that COVID-19 is having on schools and the public in general. As such, we may have last minute cancellations or postponements of school contacts. As always, I will try to provide everyone with near-real-time updates. Watch for future COVID-19 related announcements at https://www.ariss.org/
The following schools have now been postponed or cancelled due to COVID-19:
Postponed:
No new schools
Cancelled:
No new schools
****************************************************************************************************************************************
Note, all times are approximate. It is recommended that you do your own
orbital prediction or start listening about 10 minutes before the listed
time.
All dates and times listed follow International Standard ISO 8601 date and
time format YYYY-MM-DD HH:MM:SS
The complete schedule page has been updated as of 2020-11-26 05:00 UTC. (***)
Here you will find a listing of all scheduled school contacts, and
questions, other ISS related websites, IRLP and Echolink websites, and
instructions for any contact that may be streamed live.
https://www.amsat.org/amsat/ariss/news/arissnews.rtf
https://www.amsat.org/amsat/ariss/news/arissnews.txt
The successful school list has been updated as of 2020-10-14 18:00 UTC.
https://www.amsat.org/amsat/ariss/news/Successful_ARISS_schools.rtf
The ARISS webpage is at https://www.ariss.org/
Note that there are links to other ARISS websites from this site.
The main page for Applying to Host a Scheduled Contact may be found at https://www.ariss.org/apply-to-host-an-ariss-contact.html
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ARISS Contact Applications (United States)
The Amateur Radio on the International Space Station (ARISS) Program is seeking formal and informal education institutions and organizations, individually or working together, to host an Amateur Radio contact with a crew member on board the ISS. ARISS anticipates that the contact would be held between July 1, 2021 and December 30,
2021. Crew scheduling and ISS orbits will determine the exact contact dates. To maximize these radio contact opportunities, ARISS is looking for organizations that will draw large numbers of participants and integrate the contact into a well-developed education plan.
The deadline to submit a proposal is November 24th, 2020. Proposal information and more details such as expectations, proposal guidelines and the proposal form can be found at www.ariss.org. An ARISS Introductory Webinar session will be held on October 8, 2020 at 8PM ET. The Eventbrite link to sign up is: https://ariss-proposal-webinar-fall-2020.eventbrite.com
The Opportunity
Crew members aboard the International Space Station will participate in scheduled Amateur Radio contacts. These radio contacts are approximately 10 minutes in length and allow students to interact with the astronauts through a question-and-answer session.
An ARISS contact is a voice-only communication opportunity via Amateur Radio between astronauts and cosmonauts aboard the space station and classrooms and communities. ARISS contacts afford education audiences the opportunity to learn firsthand from astronauts what it is like to live and work in space and to learn about space research conducted on the ISS. Students also will have an opportunity to learn about satellite communication, wireless technology, and radio science.
Because of the nature of human spaceflight and the complexity of scheduling activities aboard the ISS, organizations must demonstrate flexibility to accommodate changes in dates and times of the radio contact.
Amateur Radio organizations around the world with the support of NASA and space agencies in Russia, Canada, Japan and Europe present educational organizations with this opportunity. The ham radio organizations’ volunteer efforts provide the equipment and operational support to enable communication between crew on the ISS and students
around the world using Amateur Radio.
Please direct any questions to [email protected].
For future proposal information and more details such as expectations, proposal guidelines and proposal form, and dates and times of Information Webinars, go to www.ariss.org.
About ARISS:
Amateur Radio on the International Space Station (ARISS) is a cooperative venture of international amateur radio societies and the space agencies that support the International Space Station (ISS). In the United States, sponsors are the Radio Amateur Satellite Corporation (AMSAT), the American Radio Relay League (ARRL), the ISS National Lab and National Aeronautics and Space Administration (NASA). The primary goal of ARISS is to promote exploration of science, technology, engineering, and mathematics (STEAM) topics by organizing scheduled contacts via amateur radio between crew members aboard the ISS and students in classrooms or public forms. Before and during these radio contacts, students, educators, parents, and communities learn about space, space technologies, and amateur radio. For more information, see www.ariss.org.
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ARISS Contact Applications (Europe, Africa and the Middle East)
Schools and Youth organizations in Europe, Africa and the Middle East interested in setting up an ARISS radio contact with an astronaut on board the International Space Station are invited to submit an application from September to October and from February to April.
Please refer to details and the application form at www.ariss-eu.org/school-contacts. Applications should be addressed by email to: [email protected]
ARISS Contact Applications (Canada, Central and South America, Asia and Australia and Russia)
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Organizations outside the United States can apply for an ARISS contact by filling out an application. Please direct questions to the appropriate regional representative listed below. If your country is not specifically listed, send your questions to the nearest ARISS Region listed. If you are unsure which address to use, please send your question to the ARISS-Canada representative; they will forward your question to the appropriate coordinator.
For the application, go to: https://www.ariss.org/ariss-application.html.
ARISS-Canada and the Americas, except USA: Steve McFarlane, VE3TBD email to: [email protected]
ARISS-Japan, Asia, Pacific and Australia: Satoshi Yasuda, 7M3TJZ email to: [email protected], Japan Amateur Radio League (JARL) https://www.jarl.org/
ARISS-Russia: Soyuz Radioljubitelei Rossii (SRR) https://srr.ru/
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ARISS is always glad to receive listener reports for the above contacts. ARISS thanks everyone in advance for their assistance. Feel free to send your reports to [email protected] or [email protected].
Listen for the ISS on the downlink of 145.8Ø MHz unless otherwise noted.
*******************************************************************************
All ARISS contacts are made via the Kenwood radio unless otherwise noted.
*******************************************************************************
Several of you have sent me emails asking about the RAC ARISS website and not being able to get in. That has now been changed to https://www.ariss.org/
Note that there are links to other ARISS websites from this site.
****************************************************************************
Looking for something new to do? How about receiving DATV from the ISS? Please note that the HamTV system has been brought back to earth for troubleshooting. Please monitor ARISS-EU or ARISS-ON for the very latest news on the troubleshooting efforts.
If interested, then please go to the ARISS-EU website for complete details. Look for the buttons indicating Ham Video.
If you need some assistance, ARISS mentor Kerry N6IZW, might be able to provide some insight. Contact Kerry at [email protected]
The HamTV webpage: https://www.amsat-on.be/hamtv-summary/
**************************************************************************** ARISS congratulations the following mentors who have now mentored over 100 schools:
Francesco IKØWGF with 140
Satoshi 7M3TJZ with 138
Sergey RV3DR with 137
Gaston ON4WF with 123
****************************************************************************
The webpages listed below were all reviewed for accuracy. Out of date
webpages were removed, and new ones have been added. If there are additional
ARISS websites I need to know about, please let me know.
Total number of ARISS ISS to earth school events is 1403.
Each school counts as 1 event.
Total number of ARISS ISS to earth school contacts is 1336.
Each contact may have multiple schools sharing the same time slot.
Total number of ARISS supported terrestrial contacts is 48.
Please feel free to contact me if more detailed statistics are needed.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
The following US states and entities have never had an ARISS contact: South Dakota, Wyoming, American Samoa, Guam, Northern Marianas Islands, and the Virgin Islands.
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QSL information may be found at:
https://www.ariss.org/qsl-cards.html
ISS callsigns: DPØISS, IRØISS, NA1SS, OR4ISS, RSØISS
****************************************************************************
Frequency chart for packet, voice, and crossband repeater modes showing
Doppler correction as of 2005-07-29 04:00 UTC
https://www.amsat.org/amsat/ariss/news/ISS_frequencies_and_Doppler_correctio...
Check out the Zoho reports of the ARISS contacts
https://reports.zoho.com/ZDBDataSheetView.cc?DBID=412218000000020415
****************************************************************************
Exp. 63 now on orbit
Kate Rubins KG5FYJ
Sergey Ryzhikov
Sergey Kud-Sverchkov
SpaceX-Crew 1 now on orbit
Victor Glover KI5BKC
Mike Hopkins KF5LJG
Soichi Noguchi KD5TVP
Shannon Walker KD5DXB
****************************************************************************
73,
Charlie Sufana AJ9N One of the ARISS operation team mentors
Hi Tony: Thanks for giving me a topic for my next CQ Antenna Column. This topic comes up every few years and also affects the hams who mount a vertically polarized Yagi on a vertical mast. On the antenna range you quickly see that metal (or even plastics) near the tip of a Yagi element moves it down in frequency. When I have a Yagi on the range, I put a small bit of Yagi element on a stick and hold it near each element while watching gain. Get the metal near the tip and gain goes up, Element too Short!Get the metal near the tip and gain goes down. Element too Long! This lets you do a quick look at how well the Yagi is working. So it is the supporting mast near an element tip that does the detuning.With a non-conductive mast what do you do with the coax? Did you run it back down your fiberglass mast? You just #@$%! your non-conductive mast with a conductor. Yes, I did measure a few tenths of a dB degradation, but the alternative is a long loop of coax out the back of the antenna. How much loss do you think is in that loop? So mounting the Crossed Yagi so that both sets of elements are 45 deg to the mast and midway between element sets is the 2nd best solution. Best solution would of course be end mounting. But that his it's own problems if you have a lot of elements! Coax can be run back along the Yagi boom and along the mast with no measurable effects.
Also extend the mast just enough for the antenna clamp to get a good grip. That is, have the mast extend only an inch or so beyond the clamps.
Yes, had an interesting talk with Mr. LFA at Dayton several years ago. I pointed out that the antenna he had on display could NOT have produced that polar plot! He was simplifying his model to get a cleaner plot. .
Kent WA5VJB/2E0VAA/G8EMY PS As an FYI don't think the solution is a Carbon Fiber boom. At Microwave Update I demonstrated a 915 MHz Yagi made using Carbon Fiber Rod for the elements. Gain about the same as Aluminum. Another FYI. Voyager 1 and 2 use a 10 foot Carbon Fiber parabolic dish antenna. They took the antennas out on the antenna range and they meet specification. As a weight saving they were NOT metalized.
Subject: Re: [amsat-bb] Fiberglass Cross-boom Alternative? To: Tony [email protected], [email protected] [email protected]
Don't dismiss using a metal cross-boom. People say it won't work without actually examining the problem. When antenna guru Kent Britain, WA5VJB looked at the problem he found a metal boom to work quite well. He then tested it on the antenna range and verified it worked. You can see the paper he presented at an AMSAT symposium here: Using Metal Cross Booms w/ Satellite Antennas
When I had a permanent satellite station I used a metal cross-boom, and there were several others in the OSCAR-13 and AO-40 era that did.
73, Gary "Joe", kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Tony via AMSAT-BB Sent: Tuesday, November 24, 2020 6:00 PM To: AMSAT-BB [email protected] Subject: [amsat-bb] Fiberglass Cross-boom Alternative?
All:
Is there a cheaper non-metallic alternative to fiberglass cross booms? Or maybe a wholesale fiberglass rod distributor that has such a beast at a reasonable price?
Tony -K2MO | | | | Using Metal Cross Booms w/ Satellite Antennas
|
|
|
Kent,
Thanks, good tips for antenna builders.
But it all boils down to what one wish to do with the antenna, as far as LEO’s are concerned getting the max from a Yagi antenna is not that important. So Tony does not have to worry to much about the boom.
I agree with your observations and also about Mr LFA claims, as I studied his designs and build a few and found also many flaws that he tends to minimise. However to his credit it is a superb antenna concept.
My philosophy is to avoid (as much as practically possible) any metallic object except the elements as far as possible which makes the design as close as possible to the existing models prediction. Actually I am building a 3M dish and the feed support is all fiberglass, using resins and epoxy glue. Sure the coax or waveguide effect cannot be avoided but taking it at the end for Yagi's and in the centre for a dish minimise negative effect of same (which is quite difficult to model or predict, at least for me).
End-mounting is the best for Yagi’s and I am presently building an array for 70cm (inspired from the Cal-Poly EME experiments) with this configuration, but this is not possible for the long VHF LFA I am also building (7m long).
In my opinion it is all compromises and depending on what you want to achieve within your environment, means, available material in the hardware and building skills, there is no silver bullet.
But what a fun building your own antennas and get better result than commercially available ones at much lower cost.
73
Jean Marc (3B8DU)
On Nov 27, 2020, at 10:26 PM, KENT BRITAIN via AMSAT-BB [email protected] wrote:
Hi Tony: Thanks for giving me a topic for my next CQ Antenna Column. This topic comes up every few years and also affects the hams who mount a vertically polarized Yagi on a vertical mast. On the antenna range you quickly see that metal (or even plastics) near the tip of a Yagi element moves it down in frequency. When I have a Yagi on the range, I put a small bit of Yagi element on a stick and hold it near each element while watching gain. Get the metal near the tip and gain goes up, Element too Short!Get the metal near the tip and gain goes down. Element too Long! This lets you do a quick look at how well the Yagi is working. So it is the supporting mast near an element tip that does the detuning.With a non-conductive mast what do you do with the coax? Did you run it back down your fiberglass mast? You just #@$%! your non-conductive mast with a conductor. Yes, I did measure a few tenths of a dB degradation, but the alternative is a long loop of coax out the back of the antenna. How much loss do you think is in that loop? So mounting the Crossed Yagi so that both sets of elements are 45 deg to the mast and midway between element sets is the 2nd best solution. Best solution would of course be end mounting. But that his it's own problems if you have a lot of elements! Coax can be run back along the Yagi boom and along the mast with no measurable effects.
Also extend the mast just enough for the antenna clamp to get a good grip. That is, have the mast extend only an inch or so beyond the clamps.
Yes, had an interesting talk with Mr. LFA at Dayton several years ago. I pointed out that the antenna he had on display could NOT have produced that polar plot! He was simplifying his model to get a cleaner plot. .
Kent WA5VJB/2E0VAA/G8EMY PS As an FYI don't think the solution is a Carbon Fiber boom. At Microwave Update I demonstrated a 915 MHz Yagi made using Carbon Fiber Rod for the elements. Gain about the same as Aluminum. Another FYI. Voyager 1 and 2 use a 10 foot Carbon Fiber parabolic dish antenna. They took the antennas out on the antenna range and they meet specification. As a weight saving they were NOT metalized.
Subject: Re: [amsat-bb] Fiberglass Cross-boom Alternative? To: Tony [email protected], [email protected] [email protected]
Don't dismiss using a metal cross-boom. People say it won't work without actually examining the problem. When antenna guru Kent Britain, WA5VJB looked at the problem he found a metal boom to work quite well. He then tested it on the antenna range and verified it worked. You can see the paper he presented at an AMSAT symposium here: Using Metal Cross Booms w/ Satellite Antennas
When I had a permanent satellite station I used a metal cross-boom, and there were several others in the OSCAR-13 and AO-40 era that did.
73, Gary "Joe", kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Tony via AMSAT-BB Sent: Tuesday, November 24, 2020 6:00 PM To: AMSAT-BB [email protected] Subject: [amsat-bb] Fiberglass Cross-boom Alternative?
All:
Is there a cheaper non-metallic alternative to fiberglass cross booms? Or maybe a wholesale fiberglass rod distributor that has such a beast at a reasonable price?
Tony -K2MO | | | | Using Metal Cross Booms w/ Satellite Antennas
|
|
|
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
The problem is anything near the element changes it's resonate frequency.Even plastics. That's why I prefer actual measurements.
The software programs are very useful, but I rarely publish a design I have not built and tested on the antenna range. Tooooo many holes in those simulations program. So far we have found 3 families of antennas that even HFSS cannot simulate.Oh you run them though HFSS but the results do not come even close to antennarange findings. Did learn an interesting technique this week.Would you like to build a 20 element Yagi for 160 Meters on a boom about 20 mm long?After you finish construction just put it in a Bose-Einstein condensate. 73 Kent WA5VJB
On Saturday, November 28, 2020, 10:41:45 AM CST, Jean Marc Momple [email protected] wrote:
Kent,
Thanks, good tips for antenna builders.
But it all boils down to what one wish to do with the antenna, as far as LEO’s are concerned getting the max from a Yagi antenna is not that important. So Tony does not have to worry to much about the boom.
I agree with your observations and also about Mr LFA claims, as I studied his designs and build a few and found also many flaws that he tends to minimise. However to his credit it is a superb antenna concept.
My philosophy is to avoid (as much as practically possible) any metallic object except the elements as far as possible which makes the design as close as possible to the existing models prediction. Actually I am building a 3M dish and the feed support is all fiberglass, using resins and epoxy glue. Sure the coax or waveguide effect cannot be avoided but taking it at the end for Yagi's and in the centre for a dish minimise negative effect of same (which is quite difficult to model or predict, at least for me).
End-mounting is the best for Yagi’s and I am presently building an array for 70cm (inspired from the Cal-Poly EME experiments) with this configuration, but this is not possible for the long VHF LFA I am also building (7m long).
In my opinion it is all compromises and depending on what you want to achieve within your environment, means, available material in the hardware and building skills, there is no silver bullet.
But what a fun building your own antennas and get better result than commercially available ones at much lower cost.
73
Jean Marc (3B8DU)
On Nov 27, 2020, at 10:26 PM, KENT BRITAIN via AMSAT-BB [email protected] wrote:
Hi Tony: Thanks for giving me a topic for my next CQ Antenna Column. This topic comes up every few years and also affects the hams who mount a vertically polarized Yagi on a vertical mast. On the antenna range you quickly see that metal (or even plastics) near the tip of a Yagi element moves it down in frequency. When I have a Yagi on the range, I put a small bit of Yagi element on a stick and hold it near each element while watching gain. Get the metal near the tip and gain goes up, Element too Short!Get the metal near the tip and gain goes down. Element too Long! This lets you do a quick look at how well the Yagi is working. So it is the supporting mast near an element tip that does the detuning.With a non-conductive mast what do you do with the coax? Did you run it back down your fiberglass mast? You just #@$%! your non-conductive mast with a conductor. Yes, I did measure a few tenths of a dB degradation, but the alternative is a long loop of coax out the back of the antenna. How much loss do you think is in that loop? So mounting the Crossed Yagi so that both sets of elements are 45 deg to the mast and midway between element sets is the 2nd best solution. Best solution would of course be end mounting. But that his it's own problems if you have a lot of elements! Coax can be run back along the Yagi boom and along the mast with no measurable effects.
Also extend the mast just enough for the antenna clamp to get a good grip. That is, have the mast extend only an inch or so beyond the clamps.
Yes, had an interesting talk with Mr. LFA at Dayton several years ago. I pointed out that the antenna he had on display could NOT have produced that polar plot! He was simplifying his model to get a cleaner plot. .
Kent WA5VJB/2E0VAA/G8EMY PS As an FYI don't think the solution is a Carbon Fiber boom. At Microwave Update I demonstrated a 915 MHz Yagi made using Carbon Fiber Rod for the elements. Gain about the same as Aluminum. Another FYI. Voyager 1 and 2 use a 10 foot Carbon Fiber parabolic dish antenna. They took the antennas out on the antenna range and they meet specification. As a weight saving they were NOT metalized.
Subject: Re: [amsat-bb] Fiberglass Cross-boom Alternative? To: Tony [email protected], [email protected] [email protected]
Don't dismiss using a metal cross-boom. People say it won't work without actually examining the problem. When antenna guru Kent Britain, WA5VJB looked at the problem he found a metal boom to work quite well. He then tested it on the antenna range and verified it worked. You can see the paper he presented at an AMSAT symposium here: Using Metal Cross Booms w/ Satellite Antennas
When I had a permanent satellite station I used a metal cross-boom, and there were several others in the OSCAR-13 and AO-40 era that did.
73, Gary "Joe", kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Tony via AMSAT-BB Sent: Tuesday, November 24, 2020 6:00 PM To: AMSAT-BB [email protected] Subject: [amsat-bb] Fiberglass Cross-boom Alternative?
All:
Is there a cheaper non-metallic alternative to fiberglass cross booms? Or maybe a wholesale fiberglass rod distributor that has such a beast at a reasonable price?
Tony -K2MO | | | | Using Metal Cross Booms w/ Satellite Antennas
|
|
|
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Kent,
Tend to agree, this is why RF is still an art and whatever professional antenna designers may say (I am a ex mobile telecom executive and somehow know what I am speaking about) and HAM’s may still do some breakthrough in this fields as we may experiment many things on the whole spectrum.
Please share more on your idea about the 160m antenna. But fail to understand how the Bose-Einstein condensate is applied there, may be you may enlighten us.
Anyway it just fun and these exchanges bring ideas.
73
Jean Marc (3B8DU)
On Nov 28, 2020, at 9:05 PM, KENT BRITAIN [email protected] wrote:
The problem is anything near the element changes it's resonate frequency. Even plastics. That's why I prefer actual measurements.
The software programs are very useful, but I rarely publish a design I have not built and tested on the antenna range. Tooooo many holes in those simulations program.
So far we have found 3 families of antennas that even HFSS cannot simulate. Oh you run them though HFSS but the results do not come even close to antenna range findings.
Did learn an interesting technique this week. Would you like to build a 20 element Yagi for 160 Meters on a boom about 20 mm long? After you finish construction just put it in a Bose-Einstein condensate.
73 Kent WA5VJB
On Saturday, November 28, 2020, 10:41:45 AM CST, Jean Marc Momple [email protected] wrote:
Kent,
Thanks, good tips for antenna builders.
But it all boils down to what one wish to do with the antenna, as far as LEO’s are concerned getting the max from a Yagi antenna is not that important. So Tony does not have to worry to much about the boom.
I agree with your observations and also about Mr LFA claims, as I studied his designs and build a few and found also many flaws that he tends to minimise. However to his credit it is a superb antenna concept.
My philosophy is to avoid (as much as practically possible) any metallic object except the elements as far as possible which makes the design as close as possible to the existing models prediction. Actually I am building a 3M dish and the feed support is all fiberglass, using resins and epoxy glue. Sure the coax or waveguide effect cannot be avoided but taking it at the end for Yagi's and in the centre for a dish minimise negative effect of same (which is quite difficult to model or predict, at least for me).
End-mounting is the best for Yagi’s and I am presently building an array for 70cm (inspired from the Cal-Poly EME experiments) with this configuration, but this is not possible for the long VHF LFA I am also building (7m long).
In my opinion it is all compromises and depending on what you want to achieve within your environment, means, available material in the hardware and building skills, there is no silver bullet.
But what a fun building your own antennas and get better result than commercially available ones at much lower cost.
73
Jean Marc (3B8DU)
On Nov 27, 2020, at 10:26 PM, KENT BRITAIN via AMSAT-BB <[email protected] mailto:[email protected]> wrote:
Hi Tony: Thanks for giving me a topic for my next CQ Antenna Column. This topic comes up every few years and also affects the hams who mount a vertically polarized Yagi on a vertical mast. On the antenna range you quickly see that metal (or even plastics) near the tip of a Yagi element moves it down in frequency. When I have a Yagi on the range, I put a small bit of Yagi element on a stick and hold it near each element while watching gain. Get the metal near the tip and gain goes up, Element too Short!Get the metal near the tip and gain goes down. Element too Long! This lets you do a quick look at how well the Yagi is working. So it is the supporting mast near an element tip that does the detuning.With a non-conductive mast what do you do with the coax? Did you run it back down your fiberglass mast? You just #@$%! your non-conductive mast with a conductor. Yes, I did measure a few tenths of a dB degradation, but the alternative is a long loop of coax out the back of the antenna. How much loss do you think is in that loop? So mounting the Crossed Yagi so that both sets of elements are 45 deg to the mast and midway between element sets is the 2nd best solution. Best solution would of course be end mounting. But that his it's own problems if you have a lot of elements! Coax can be run back along the Yagi boom and along the mast with no measurable effects.
Also extend the mast just enough for the antenna clamp to get a good grip. That is, have the mast extend only an inch or so beyond the clamps.
Yes, had an interesting talk with Mr. LFA at Dayton several years ago. I pointed out that the antenna he had on display could NOT have produced that polar plot! He was simplifying his model to get a cleaner plot. .
Kent WA5VJB/2E0VAA/G8EMY PS As an FYI don't think the solution is a Carbon Fiber boom. At Microwave Update I demonstrated a 915 MHz Yagi made using Carbon Fiber Rod for the elements. Gain about the same as Aluminum. Another FYI. Voyager 1 and 2 use a 10 foot Carbon Fiber parabolic dish antenna. They took the antennas out on the antenna range and they meet specification. As a weight saving they were NOT metalized.
Subject: Re: [amsat-bb] Fiberglass Cross-boom Alternative? To: Tony <[email protected] mailto:[email protected]>, [email protected] mailto:[email protected] <[email protected] mailto:[email protected]>
Don't dismiss using a metal cross-boom. People say it won't work without actually examining the problem. When antenna guru Kent Britain, WA5VJB looked at the problem he found a metal boom to work quite well. He then tested it on the antenna range and verified it worked. You can see the paper he presented at an AMSAT symposium here: Using Metal Cross Booms w/ Satellite Antennas
When I had a permanent satellite station I used a metal cross-boom, and there were several others in the OSCAR-13 and AO-40 era that did.
73, Gary "Joe", kk0sd
-----Original Message----- From: AMSAT-BB <[email protected] mailto:[email protected]> On Behalf Of Tony via AMSAT-BB Sent: Tuesday, November 24, 2020 6:00 PM To: AMSAT-BB <[email protected] mailto:[email protected]> Subject: [amsat-bb] Fiberglass Cross-boom Alternative?
All:
Is there a cheaper non-metallic alternative to fiberglass cross booms? Or maybe a wholesale fiberglass rod distributor that has such a beast at a reasonable price?
Tony -K2MO | | | | Using Metal Cross Booms w/ Satellite Antennas
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Sent via [email protected]. mailto:[email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb https://www.amsat.org/mailman/listinfo/amsat-bb
Yes, imagine a 145 MHz antenna build using 100 mm diameter elements. We see good gain and very very broad frequency response with extremely good Return Loss. We are using these in RFID applications where the antenna is used to transmit and receive at the same time.
NEC does everything as an infinitesimal line. Change the diameter of the element, and NEC changes the length of the line to compensate for the change in inductance. HFSS doesn't do any better. Haven't tried it on any of the Time Domain programs. So far all work has been on network analyzers and the antenna range.
The Bose Condensate is any interesting 'fluid' that only exists a few thousands of a degree above absolute Zero. It drastically changes the speed of light. Kent
On Saturday, November 28, 2020, 11:26:41 AM CST, Jean Marc Momple [email protected] wrote:
Kent, Tend to agree, this is why RF is still an art and whatever professional antenna designers may say (I am a ex mobile telecom executive and somehow know what I am speaking about) and HAM’s may still do some breakthrough in this fields as we may experiment many things on the whole spectrum. Please share more on your idea about the 160m antenna. But fail to understand how the Bose-Einstein condensate is applied there, may be you may enlighten us. Anyway it just fun and these exchanges bring ideas. 73
Jean Marc (3B8DU)
On Nov 28, 2020, at 9:05 PM, KENT BRITAIN [email protected] wrote: The problem is anything near the element changes it's resonate frequency.Even plastics. That's why I prefer actual measurements.
The software programs are very useful, but I rarely publish a design I have not built and tested on the antenna range. Tooooo many holes in those simulations program. So far we have found 3 families of antennas that even HFSS cannot simulate.Oh you run them though HFSS but the results do not come even close to antennarange findings. Did learn an interesting technique this week.Would you like to build a 20 element Yagi for 160 Meters on a boom about 20 mm long?After you finish construction just put it in a Bose-Einstein condensate. 73 Kent WA5VJB
On Saturday, November 28, 2020, 10:41:45 AM CST, Jean Marc Momple [email protected] wrote:
Kent,
Thanks, good tips for antenna builders.
But it all boils down to what one wish to do with the antenna, as far as LEO’s are concerned getting the max from a Yagi antenna is not that important. So Tony does not have to worry to much about the boom.
I agree with your observations and also about Mr LFA claims, as I studied his designs and build a few and found also many flaws that he tends to minimise. However to his credit it is a superb antenna concept.
My philosophy is to avoid (as much as practically possible) any metallic object except the elements as far as possible which makes the design as close as possible to the existing models prediction. Actually I am building a 3M dish and the feed support is all fiberglass, using resins and epoxy glue. Sure the coax or waveguide effect cannot be avoided but taking it at the end for Yagi's and in the centre for a dish minimise negative effect of same (which is quite difficult to model or predict, at least for me).
End-mounting is the best for Yagi’s and I am presently building an array for 70cm (inspired from the Cal-Poly EME experiments) with this configuration, but this is not possible for the long VHF LFA I am also building (7m long).
In my opinion it is all compromises and depending on what you want to achieve within your environment, means, available material in the hardware and building skills, there is no silver bullet.
But what a fun building your own antennas and get better result than commercially available ones at much lower cost.
73
Jean Marc (3B8DU)
On Nov 27, 2020, at 10:26 PM, KENT BRITAIN via AMSAT-BB [email protected] wrote:
Hi Tony: Thanks for giving me a topic for my next CQ Antenna Column. This topic comes up every few years and also affects the hams who mount a vertically polarized Yagi on a vertical mast. On the antenna range you quickly see that metal (or even plastics) near the tip of a Yagi element moves it down in frequency. When I have a Yagi on the range, I put a small bit of Yagi element on a stick and hold it near each element while watching gain. Get the metal near the tip and gain goes up, Element too Short!Get the metal near the tip and gain goes down. Element too Long! This lets you do a quick look at how well the Yagi is working. So it is the supporting mast near an element tip that does the detuning.With a non-conductive mast what do you do with the coax? Did you run it back down your fiberglass mast? You just #@$%! your non-conductive mast with a conductor. Yes, I did measure a few tenths of a dB degradation, but the alternative is a long loop of coax out the back of the antenna. How much loss do you think is in that loop? So mounting the Crossed Yagi so that both sets of elements are 45 deg to the mast and midway between element sets is the 2nd best solution. Best solution would of course be end mounting. But that his it's own problems if you have a lot of elements! Coax can be run back along the Yagi boom and along the mast with no measurable effects.
Also extend the mast just enough for the antenna clamp to get a good grip. That is, have the mast extend only an inch or so beyond the clamps.
Yes, had an interesting talk with Mr. LFA at Dayton several years ago. I pointed out that the antenna he had on display could NOT have produced that polar plot! He was simplifying his model to get a cleaner plot. .
Kent WA5VJB/2E0VAA/G8EMY PS As an FYI don't think the solution is a Carbon Fiber boom. At Microwave Update I demonstrated a 915 MHz Yagi made using Carbon Fiber Rod for the elements. Gain about the same as Aluminum. Another FYI. Voyager 1 and 2 use a 10 foot Carbon Fiber parabolic dish antenna. They took the antennas out on the antenna range and they meet specification. As a weight saving they were NOT metalized.
Subject: Re: [amsat-bb] Fiberglass Cross-boom Alternative? To: Tony [email protected], [email protected] [email protected]
Don't dismiss using a metal cross-boom. People say it won't work without actually examining the problem. When antenna guru Kent Britain, WA5VJB looked at the problem he found a metal boom to work quite well. He then tested it on the antenna range and verified it worked. You can see the paper he presented at an AMSAT symposium here: Using Metal Cross Booms w/ Satellite Antennas
When I had a permanent satellite station I used a metal cross-boom, and there were several others in the OSCAR-13 and AO-40 era that did.
73, Gary "Joe", kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Tony via AMSAT-BB Sent: Tuesday, November 24, 2020 6:00 PM To: AMSAT-BB [email protected] Subject: [amsat-bb] Fiberglass Cross-boom Alternative?
All:
Is there a cheaper non-metallic alternative to fiberglass cross booms? Or maybe a wholesale fiberglass rod distributor that has such a beast at a reasonable price?
Tony -K2MO | | | | Using Metal Cross Booms w/ Satellite Antennas
|
|
|
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
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Jean Marc Momple -
KENT BRITAIN